Dishwasher appliances generally have a wash chamber that includes one or more racks for the receipt of dishes, pots, pans, and other articles for washing. For example, an upper rack may be provided for glasses, cups, and smaller utensils while a lower rack may be provided for larger items such as pots, pans, and plates. In order to accommodate articles of different sizes, a mechanism for the height adjustment of one or more racks may be provided. One or more upper racks, for example, may be adjustable between different height levels in the dishwasher so that larger items can be placed either into the upper rack by adjusting it to a lower level or into the lower rack by adjusting the upper rack to a higher level. Other configurations for height adjustment of one or more racks may be used as well.
Frequently, one or more fluid conduits may be attached to the bottom of an upper rack in the dishwasher. This conduit may supply fluid to e.g., a spray arm that provides wash fluid at a mid-level location in the dishwasher. For a dishwasher appliance with a front loading door, the racks are typically equipped to slide or roll into and out of the wash chamber so that the user can place or remove articles in the racks. As a result, where a conduit is attached to a movable rack, provision must be made for connecting the conduit with a fluid supply that is usually located toward the rear of the wash chamber. Preferably the connection with a fluid supply will be releasable and self-sealing so that it functions automatically as the user slides the rack assembly in or out of the dishwasher.
Where a rack assembly is height adjustable, challenges are created when providing such a connection for a fluid conduit carried on the rack assembly. These changes in height for the rack necessarily require that the connection point for the fluid conduit will also change height and, therefore, will contact the fluid supply at different locations. One approach to providing such a connection is to provide a docking station having a single docking port to which a conduit attached to the rack assembly may dock. The conduit includes a chamber and a check valve plate having two check valves with closure protrusions extending therefrom. When the conduit is docked in an upper position, one of the check valves is opened to allow a fluid flow into the conduit and the other check valve is closed. In contrast, when the conduit is docked in a lower position, the check valve previously closed is now open and the check valve previously opened is now closed. One challenge with such approach is that the closure protrusions of the check valves obstruct the fluid flow through the chamber despite being into the open position. As a result, the fluid flow to the spray arm is not optimized. Another approach to providing such a connection is to create multiple docking ports each configured for allowing a fluid flow therethrough and each positioned at a predetermined height along a vertically extending fluid supply conduit depending upon the fixed height levels for the rack. This approach requires that each docking port includes a sealing mechanism so that fluid is not released from one port when the conduit is connected to another port at a different level during operation of the dishwasher. Unfortunately, this can add unwanted complexity to the manufacture, assembly, and operation of the dishwasher.
Accordingly, an adjustable conduit and docking assembly having a conduit carried by a rack in a dishwasher appliance that addresses one or more of the challenges noted above would be beneficial.